:root{--bg-primary: #0f111a;--bg-secondary: #1a1d2d;--bg-sidebar: #0a0c14;--accent-primary: #6366f1;--accent-secondary: #8b5cf6;--text-primary: #f8fafc;--text-secondary: #94a3b8;--border-color: rgba(255, 255, 255, .08);--glass-bg: rgba(255, 255, 255, .03);--glass-border: rgba(255, 255, 255, .06);--hard-color: #ef4444;--medium-color: #f59e0b;--easy-color: #10b981;--card-shadow: 0 10px 30px rgba(0, 0, 0, .5);--transition: all .3s cubic-bezier(.4, 0, .2, 1)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Inter,sans-serif;background-color:var(--bg-primary);color:var(--text-primary);overflow-x:hidden}h1,h2,h3,h4{font-family:Outfit,sans-serif}.app-container{display:flex;min-height:100vh}.sidebar{width:280px;background-color:var(--bg-sidebar);border-right:1px solid var(--border-color);display:flex;flex-direction:column;padding:2rem 1.5rem;position:sticky;top:0;height:100vh}.logo{display:flex;align-items:center;gap:.75rem;font-size:1.5rem;font-weight:700;margin-bottom:3rem;color:var(--accent-primary)}.nav-section{margin-bottom:2.5rem}.nav-section h3{font-size:.75rem;text-transform:uppercase;letter-spacing:.1em;color:var(--text-secondary);margin-bottom:1.25rem}.filter-group{display:flex;flex-direction:column;gap:.75rem}.filter-item{display:flex;align-items:center;gap:.75rem;cursor:pointer;font-size:.95rem;color:var(--text-secondary);transition:var(--transition)}.filter-item:hover{color:var(--text-primary)}.filter-item input{accent-color:var(--accent-primary);width:1.1rem;height:1.1rem}.chip{padding:.2rem .6rem;border-radius:4px;font-size:.75rem;font-weight:600;text-transform:uppercase}.chip.hard{background-color:#ef44441a;color:var(--hard-color)}.chip.medium{background-color:#f59e0b1a;color:var(--medium-color)}.chip.easy{background-color:#10b9811a;color:var(--easy-color)}.main-content{flex:1;display:flex;flex-direction:column}.top-bar{height:80px;display:flex;align-items:center;justify-content:space-between;padding:0 2.5rem;background-color:#0f111acc;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--border-color);position:sticky;top:0;z-index:10}.search-container{display:flex;align-items:center;background-color:var(--bg-secondary);border:1px solid var(--glass-border);padding:.6rem 1.2rem;border-radius:99px;width:400px;gap:.75rem}.search-container i{color:var(--text-secondary)}.search-container input{background:none;border:none;color:var(--text-primary);width:100%;outline:none;font-size:.95rem}.btn-icon{background:none;border:1px solid var(--glass-border);color:var(--text-secondary);width:40px;height:40px;border-radius:8px;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:var(--transition)}.btn-icon:hover,.btn-icon.active{background-color:var(--accent-primary);color:#fff;border-color:var(--accent-primary)}.content-area{padding:2.5rem}.questions-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:1.5rem}.questions-grid.list-view{grid-template-columns:1fr}.q-card{background-color:var(--bg-secondary);border:1px solid var(--glass-border);border-radius:16px;padding:1.5rem;cursor:pointer;transition:var(--transition);position:relative;overflow:hidden;display:flex;flex-direction:column}.q-card:hover{transform:translateY(-5px);border-color:var(--accent-primary);box-shadow:var(--card-shadow)}.q-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1rem}.q-id{font-size:.7rem;color:var(--text-secondary);font-weight:500}.q-meta{display:flex;gap:.5rem}.q-body{flex:1;font-size:.95rem;line-height:1.6;color:var(--text-primary);display:-webkit-box;-webkit-line-clamp:4;line-clamp:4;-webkit-box-orient:vertical;overflow:hidden;margin-bottom:1.5rem}.q-footer{display:flex;justify-content:space-between;align-items:center;font-size:.75rem;color:var(--text-secondary);padding-top:1rem;border-top:1px solid var(--border-color)}.q-domain{font-weight:500;max-width:150px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.modal{display:none;position:fixed;z-index:100;left:0;top:0;width:100%;height:100%;background-color:#000000d9;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);overflow:auto}.modal-content{background-color:var(--bg-secondary);margin:5% auto;padding:3rem;border:1px solid var(--glass-border);width:80%;max-width:900px;border-radius:24px;position:relative;box-shadow:var(--card-shadow)}.close-modal{position:absolute;right:2rem;top:2rem;font-size:2rem;cursor:pointer;color:var(--text-secondary)}.modal-body h2{margin-bottom:1.5rem;color:var(--accent-primary)}.modal-info{display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem;margin-bottom:2rem;background:var(--glass-bg);padding:1.5rem;border-radius:12px}.info-item label{display:block;font-size:.75rem;color:var(--text-secondary);margin-bottom:.25rem}.info-item span{font-weight:600}.question-full-text{font-size:1.1rem;line-height:1.7;margin-bottom:2rem}.choices-list{display:grid;grid-template-columns:1fr;gap:1rem;margin-bottom:2rem}.choice-item{padding:1rem 1.5rem;background:var(--glass-bg);border:1px solid var(--glass-border);border-radius:12px}.choice-item.correct{border-color:var(--easy-color);background:#10b9810d}.rationale-box{margin-top:2.5rem;padding:2rem;background:#6366f10d;border:1px dashed var(--accent-primary);border-radius:16px}.rationale-box h4{margin-bottom:1rem;color:var(--accent-primary)}.loader{grid-column:1 / -1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:10rem 0;gap:1rem;color:var(--text-secondary)}.spinner{width:40px;height:40px;border:3px solid var(--glass-border);border-top:3px solid var(--accent-primary);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}svg{max-width:100%;height:auto;background:#fff;padding:1rem;border-radius:8px;margin:1rem 0}